Open Access Nano Express

Interaction of silicon-based quantum dots with gibel carp liver: oxidative and structural modifications

Loredana Stanca1, Sorina Nicoleta Petrache1, Andreea Iren Serban12, Andrea Cristina Staicu1, Cornelia Sima3, Maria Cristina Munteanu1, Otilia Zărnescu1, Diana Dinu1* and Anca Dinischiotu1

Author Affiliations

1 Department of Biochemistry and Molecular Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest, 050095, Romania

2 Department of Preclinical Sciences, University of Agricultural Sciences and Veterinary Medicine, 105 Splaiul Independentei, Bucharest, 050097, Romania

3 Laser Department, National Institute of Laser, Plasma and Radiation Physics, 409 Atomistilor, Bucharest-Magurele, 077125, Romania

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Nanoscale Research Letters 2013, 8:254  doi:10.1186/1556-276X-8-254

Published: 29 May 2013

Abstract

Quantum dots (QDs) interaction with living organisms is of central interest due to their various biological and medical applications. One of the most important mechanisms proposed for various silicon nanoparticle-mediated toxicity is oxidative stress. We investigated the basic processes of cellular damage by oxidative stress and tissue injury following QD accumulation in the gibel carp liver after intraperitoneal injection of a single dose of 2 mg/kg body weight Si/SiO2 QDs after 1, 3, and 7 days from their administration.

QDs gradual accumulation was highlighted by fluorescence microscopy, and subsequent histological changes in the hepatic tissue were noted. After 1 and 3 days, QD-treated fish showed an increased number of macrophage clusters and fibrosis, while hepatocyte basophilia and isolated hepatolytic microlesions were observed only after substantial QDs accumulation in the liver parenchyma, at 7 days after IP injection.

Induction of oxidative stress in fish liver was revealed by the formation of malondialdehyde and advanced oxidation protein products, as well as a decrease in protein thiol groups and reduced glutathione levels. The liver enzymatic antioxidant defense was modulated to maintain the redox status in response to the changes initiated by Si/SiO2 QDs. So, catalase and glutathione peroxidase activities were upregulated starting from the first day after injection, while the activity of superoxide dismutase increased only after 7 days. The oxidative damage that still occurred may impair the activity of more sensitive enzymes. A significant inhibition in glucose-6-phosphate dehydrogenase and glutathione-S-transferase activity was noted, while glutathione reductase remained unaltered.

Taking into account that the reduced glutathione level had a deep decline and the level of lipid peroxidation products remained highly increased in the time interval we studied, it appears that the liver antioxidant defense of Carassius gibelio does not counteract the oxidative stress induced 7 days after silicon-based QDs exposure in an efficient manner.

Keywords:
Silicon-based quantum dots; Gibel carp; Liver; Oxidative stress; Antioxidant enzymes; Fluorescence; 68.65.Hb; 87.85.jj; 81.07.Ta